The accurate measurement of electric power and energy is increasingly important as a way to manage costs in an ever-growing industrial economy. The trend towards deregulating the electricity utilities has reinforced the importance of accurately determining losses in the electric power grids. High voltage transformers, medium voltage and low voltage distribution transformers are critical components of the power grids.
Currently very high accuracy systems, such as Measurement International (MI) Model LMS 2000/100 are available, which are designed for measuring losses in high voltage, large power transformers, large motors and turbines. The Model LMS 2000/100 is representative of a family of Models designed, built and sold by MI worldwide.
A high voltage loss measurement system like MI Model LMS 2000/100 has:                (i) Measurement Capability: 2000A at 100 KV, 50/60 Hz. Full scale accuracy maintained over the full range of both voltage (100 KV to 1 KV) and current (2000A to 2A). Single and 3-phase measurements can be performed;        (ii) System Accuracy: Power measurements <100 PPM (parts per million) voltage and current measurements <100 PPM, accurate to 2 sigma. Currently MI Model LMS 2000/100 has the best system accuracy available in the marketplace.        
To achieve the high accuracy levels, expensive components, such as high voltage capacitors, time division multiplying (TDM) wattmeters, and capacitive voltage dividers are used.
The cost of high voltage loss measurement system precludes their practical application for measuring losses in distribution transformers, medium power motors and turbines.
Less expensive systems are available which utilize potential transformers or current transformers, e.g. Phenix Series TTS. However, the accuracies of such systems can be maintained only when full power is applied to the equipment under test. This is a serious practical limitation since transformers are expected to operate in their full range. Typical accuracy is 1,000 PPM, deteriorating to 2,000 PPM at half power, and worsening even further when power applied to the equipment under test is further reduced.
Interest in using the electrical power grid for Internet-related communications applications is growing. One undesirable side effect of this application is the presence of higher frequency waveforms, which can distort the accurate measurement of power. The systems presently available are sensitive to frequency. A loss measurement system that is insensitive to frequency characteristics up to the 6th harmonics is needed.
Accordingly, there is a need in the marketplace for a loss measurement system, insensitive to frequency characteristics, that can accurately and cost effectively measure losses in distribution transformers, medium power motors and turbines.